In this historical comparison study, the transcatheter pacemaker met the prespecified safety and efficacy goals; it had a safety profile similar to that of a transvenous system while providing low and stable pacing thresholds. (Funded by Medtronic; Micra Transcatheter Pacing Study ClinicalTrials.gov number, NCT02004873.).

Public opinion in the United States contains a paradox. The American public is symbolically conservative: it cherishes the symbols of conservatism and is more likely to identify as conservative than as liberal. Yet at the same time, it is operationally liberal, wanting government to do and spend more to solve a variety of social problems. This book focuses on understanding this contradiction. It argues that both facets of public opinion are real and lasting, not artifacts of the survey context or isolated to particular points in time. By exploring the ideological attitudes of the American public as a whole, and the seemingly conflicted choices of individual citizens, it explains the foundations of this paradox. The keys to understanding this large-scale contradiction, and to thinking about its consequences, are found in Americans' attitudes with respect to religion and culture and in the frames in which elite actors describe policy issues.

Background: Percutaneous closure of the left atrial appendage (LAA) is an alternative to chronic oral anticoagulation to reduce stroke risk in patients with non-valvular atrial fibrillation (NVAF). The Amplatzer™ Amulet™ LAA Occluder IDE Trial (Amulet IDE Trial) was designed to evaluate the safety and effectiveness of the dual-seal mechanism of the Amulet LAA occluder compared with the Watchman™ device. Methods: Patients with NVAF at increased risk of stroke were randomly assigned (1:1) to undergo percutaneous implantation of a LAA occluder with the Amulet occluder or Watchman device. The primary endpoints included safety (composite of procedure-related complications, all-cause death, or major bleeding at 12 months) and effectiveness (composite of ischemic stroke or systemic embolism at 18 months) and the rate of LAA occlusion at 45 days. Pre-specified secondary endpoints included a composite of all stroke, systemic embolism, or cardiovascular/unexplained death at 18 months, major bleeding at 18 months, and superiority test of the three primary endpoints. Results: A total of 1878 patients were enrolled. The Amulet occluder was noninferior to the Watchman device for the primary safety endpoint (14.5% vs. 14.7%; difference=-0.14, 95% CI, -3.42-3.13; p<0.001 for noninferiority). Major bleeding and all-cause death were similar between groups (10.6% vs 10.0% and 3.9% vs 5.1%, respectively). Procedure-related complications were higher for the Amulet occluder (4.5% vs. 2.5%), largely related to more frequent pericardial effusion and device embolization. The Amulet occluder was noninferior to the Watchman device for the primary effectiveness endpoint (2.8% vs. 2.8%; difference=0.00, 95% CI, -1.55-1.55; p<0.001 for non-inferiority), and the composite of stroke, systemic embolism or cardiovascular/unexplained death (5.6% vs 7.7%, difference=-2.12, 95% CI, -4.45-0.21; p<0.001 for noninferiority). The rate of major bleeding was similar between groups (11.6% vs. 12.3%; difference=-0.71, 95% CI -3.72-2.31; p=0.32 for superiority). LAA occlusion was higher for the Amulet occluder compared with the Watchman device (98.9% vs. 96.8%; difference=2.03, 95% confidence interval [CI], 0.41-3.66; p<0.001 for noninferiority; p=0.003 for superiority). Conclusions: The Amulet occluder was non-inferior for safety and effectiveness of stroke prevention for NVAF compared with the Watchman device, and superior for LAA occlusion. Procedure-related complications were higher with the Amulet device and decreased with operator experience. Clinical Trial Registration: URL https://clinicaltrials.gov Unique Identifier NCT02879448

Background: Left atrial appendage (LAA) occlusion provides an alternative to oral anticoagulation (OAC) for thromboembolic risk reduction in patients with non-valvular atrial fibrillation (NVAF). Since regulatory approval in 2015, the WATCHMAN device has been the only LAA closure device available for clinical use in the United States. The PINNACLE FLX study evaluated the safety and effectiveness of the next-generation WATCHMAN FLX LAA closure device in patients with NVAF in whom OAC is indicated, but who have an appropriate rationale to seek a non-pharmaceutical alternative. Methods: This was a prospective, non-randomized, multi-center FDA study. The primary safety endpoint was the occurrence of one of the following events within 7 days post-procedure or by hospital discharge, whichever was later: death, ischemic stroke, systemic embolism, or device- or procedure-related events requiring cardiac surgery. The primary effectiveness endpoint was the incidence of effective LAA closure (peri-device flow ≤5mm), as assessed by the echocardiography core laboratory at 12-month follow-up. Results: A total of 400 patients were enrolled. The mean age was 73.8{plus minus}8.6 years and the mean CHA2DS2-VASc score was 4.2{plus minus}1.5. The incidence of the primary safety endpoint was 0.5% with a one-sided 95% upper confidence interval (CI) of 1.6%, meeting the performance goal (PG) of 4.2% (P<0.0001). The incidence of the primary effectiveness endpoint was 100%, with a onesided 95% lower CI of 99.1%, again meeting the PG of 97.0% (P<0.0001). Device-related thrombus was reported in 7 patients, no patients experienced pericardial effusion requiring open cardiac surgery, and there were no device embolizations. Conclusions: LAA closure with this next generation LAA closure device was associated with a low incidence of adverse events and a high incidence of anatomic closure. Clinical Trial Registration: URL https://clinicaltrials.gov Unique Identifier NCT02702271

Background Recurrent atrial fibrillation (AF) occurs in up to 50 % of patients within 1 year after catheter ablation, and a clinical risk score to predict recurrence remains a critical unmet need. The aim of this study was to (1) develop a simple score for the prediction of rhythm outcome following catheter ablation; (2) compare it with the CHADS2 and CHA2DS2-VASc scores, and (3) validate it in an external cohort. Methods Rhythm outcome between 3 and 12 months after AF catheter ablation were documented. The APPLE score [one point for age>65 years, persistent AF, impaired eGFR (<60 ml/min/1.73 m2), LA diameter ≥43 mm, EF < 50 %] was associated with AF recurrence and was validated in an external cohort in 261 patients with comparable ablation and follow-up. Results In 1145 patients (60 ± 10 years, 65 % male, 62 % paroxysmal AF) the APPLE score showed better prediction of AF recurrences (AUC 0.634, 95 % CI 0.600–0.668, p < 0.001) than CHADS2 (AUC 0.538) and CHA2DS2-VASc (AUC 0.542). Compared to patients with an APPLE score of 0, the odds ratio for AF recurrences was 1.73, 2.79 and 4.70 for APPLE scores 1, 2, or ≥3, respectively (all p < 0.05). In the external validation cohort, the APPLE score showed similar results (AUC 0.624, 95 % CI 0.562–0.687, p < 0.001). Conclusions The novel APPLE score is superior to the CHADS2 and CHA2DS2-VASc scores for prediction of rhythm outcome after catheter ablation. It holds promise as a useful tool to identify patients with low, intermediate, and high risk for AF recurrence.

A laboratory experiment was performed to study the dynamically rich interaction of a turbulent open channel flow with a bed-mounted axial-flow hydrokinetic turbine. An acoustic Doppler velocimeter and a torque transducer were used to simultaneously measure at high temporal resolution the three velocity components of the flow at various locations upstream of the turbine and in the wake region and turbine power, respectively. Results show that for sufficiently low frequencies the instantaneous power generated by the turbine is modulated by the turbulent structure of the approach flow. The critical frequency above which the response of the turbine is decoupled from the turbulent flow structure is shown to vary linearly with the angular frequency of the rotor. The measurements elucidate the structure of the turbulent turbine wake, which is shown to persist for at least fifteen rotor diameters downstream of the rotor, and a new approach is proposed to quantify the wake recovery, based on the growth of the largest scale motions in the flow. Spectral analysis is employed to demonstrate the dominant effect of the tip vortices in the energy distribution in the near-wake region and uncover meandering motions.

Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure with reduced ejection fraction. Although these devices effectively improve survival, atrial and ventricular arrhythmias are common, predispose these patients to additional risk, and complicate patient management. However, there is no consensus on best practices for the medical management of these arrhythmias or on the optimal timing for procedural interventions in patients with refractory arrhythmias. Although the vast majority of these patients have preexisting cardiovascular implantable electronic devices or cardiac resynchronization therapy, given the natural history of heart failure, it is common practice to maintain cardiovascular implantable electronic device detection and therapies after LVAD implantation. Available data, however, are conflicting on the efficacy of and optimal device programming after LVAD implantation. Therefore, the primary objective of this scientific statement is to review the available evidence and to provide guidance on the management of atrial and ventricular arrhythmias in this unique patient population, as well as procedural interventions and cardiovascular implantable electronic device and cardiac resynchronization therapy programming strategies, on the basis of a comprehensive literature review by electrophysiologists, heart failure cardiologists, cardiac surgeons, and cardiovascular nurse specialists with expertise in managing these patients. The structure and design of commercially available LVADs are briefly reviewed, as well as clinical indications for device implantation. The relevant physiological effects of long-term exposure to continuous-flow circulatory support are highlighted, as well as the mechanisms and clinical significance of arrhythmias in the setting of LVAD support.

No abstract